Unintended cutaneous reactions to CS spray.

CS spray (2-chlorobenzylidene malononitrile 5% w/v in methyl isobutyl ketone) has been used by the police force in the UK as an incapacitant for nearly a decade. It causes a number of well-recognized cutaneous reactions, which are generally regarded as short-lived. These include skin burning, erythema and blistering. However, a range of unpredictable cutaneous reactions to CS spray may also occur. We have found contact allergy, leukoderma, initiation or exacerbation of seborrhoeic dermatitis, and aggravation of rosacea following CS spray exposure in 6 police officers and 1 doorman. These skin reactions have required long-term changes in working practice for the affected individuals. Police officers may have repeated exposure to CS spray during their training and in their work, and designated police officers carry CS spray canisters daily in the line of duty. They may therefore be at greater risk of exposure to CS spray and its unintended effects than many assailants.